1. Field
Example embodiments relate to a composition for preparing an organic insulating film, an organic insulating film prepared by using the same, an organic thin film transistor (OTFT) comprising the organic insulating film, an electronic device comprising the organic thin film transistor and methods of fabricating the organic insulating film, the organic thin film transistor and the electronic device. Other example embodiments relate to a composition for preparing an organic insulating film comprising an organic insulating polymer in which a photo-reactive functional group showing an increased degree of crosslinking is introduced into a side-chain, to thereby diminish hysteresis of a thin film transistor, an organic insulating film prepared by using the composition, an OTFT comprising the organic insulating film, an electronic device comprising the organic thin film transistor and methods of fabricating the organic insulating film, the organic thin film transistor and the electronic device.
2. Description of the Related Art
A thin film transistor (TFT) has been used as a switching device for controlling driving of each pixel and a driving device for each pixel in a flat panel display device, e.g., a liquid crystal display (LCD) and/or an electroluminescence display (ELD) device. The TFT may be applied to a plastic chip for a smart card or an inventory tag.
This TFT may include a source area and a drain area doped with an increased concentration of impurities, a semiconductor layer having a channel area formed between the two areas, a gate electrode disposed in an area which is insulated with the semiconductor layer and corresponds to the channel area, and a source electrode and a drain electrode contacting with the source area and the drain area, respectively.
A conventional TFT channel layer has been generally made of an inorganic semiconductor material, e.g., silicon (Si), but such inorganic-based material requires an increased cost and increased temperature vacuum process. Therefore, the inorganic-based material has been replaced by an organic-based semiconductor material so that enlargement, cost-reduction and softening of display device is possible. Thus, extensive research on an OTFT using an organic layer as a semiconductor layer is actively underway.
The OTFT may form a thin film as an insulating film through an inexpensive solution procedure, e.g., spin coating. But, trap charge may occur at an interface in view of the intrinsic characteristics of an organic-based material and hysteresis may be caused by polarization owing to external moisture along a sweep direction of gate voltage. For example, when applying a certain strength of voltage to a gate electrode, the strength of current between the source electrode and the drain electrode may correspond to the strength of the applied voltage, and such current strength must be maintained under any circumstances. However, the conventional art OTFT may not be homogeneously maintained due to the occurrence of hysteresis.